Consider bundling with zlib-ng

[fdelapena]

zlib-ng is a drop-in replacement of zlib with modern processor instructions, including NEON. Because games use lots of PNG or XYZ images that use deflate compression, there could be some benefit on loading times for some large games or on slow systems, also bringing improvements when using VFS.

Performance tests for dynamic Player builds could be done without rebuilding by using LD_PRELOAD if the downstream zlib-ng is built in zlib compatibility mode.

[carstene1ns]

For Wii this has no improvements, as it can not use POWER8 and VMX.
Only benefit I see here is for PSVita with NEON, as 3DS does also not support it.
Modern systems have enough power to do this relatively fast, and we cannot force AVX or something for our Windows/Linux builds, as it may not work everywhere.

The good thing here is we do not need to patch this library.
Defining ARM_NOCHECK_NEON for PSVita should be enough.

Question is, does it even matter if only one platform benefits from it?